I guessing that the lock tool for the 8V works in the same manner as on the twin cam JTD engines? If so, you will have a blanking plug on front of the camshaft housing that will be facing you with the engine cover removed. With the plug removed, the lock tool screws into the hole. When the engine is rotated the spring loaded plunger drops into a hole in the cam when it reaches the correct position. With the cam locked you still need to mark the crank position in case you turn it by mistakewhen belt is off as there are no reference marks on the bottom end. There is also a crank locking tool that you can get but as long as you mark the crank position you will be fine.